The present invention relates to a retention composition for dental prosthesis for application on those surfaces of the dental prosthesis which, when in position in the mouth, face the oral mucous membrane, in order to retain the dental prosthesis in position, said composition containing at least one orally acceptable retention agent which gives the composition the requisite properties for retention of the dental prosthesis, and a compound inhibiting the growth of bacteria and fungi.
Many wearers (about 50-65%) of removable dental prosthesis have trouble with their prosthesis to a greater or lesser extent. (Miller E. L., 1975, J. Dent. Assn. S.AFR. 30 (1): 89-93 and Budtz-Jorgensen E., 1978, JADA, 96, 96: 474-479). The trouble may manifest itself in different ways and the reasons may be various.
Keeping the prosthesis fixed in the intended position both during rest or relaxation and while speaking, talking but above all during movement connected with chewing, may be a problem for many people.
These inconveniences may appear even if the prosthesis is constructed in accordance with all the rules pertaining to dental artistry. The reason may be unalterable anatomic oral conditions which are unfavourable or other individual causes such as motoric insufficiency in the oral and jaw region. The latter is often the case with certain categories of people, such as old people and physically or mentally handicapped people. (Norderam E., 1977: Tandlakartidningen Vol. 69, No. 7). Inability to fix the prosthesis causes a feeling of insecurity in the individual and is often a psychological handicap in social contact with other people.
It is not unusual among denture wearers for inflammatory changes to occur in the oral mucous membrane against which the base of the prosthesis abuts. Through intensified research in this field it has now been established that the primary cause of such disease states is of microbial nature with the emphasis on the occurrence of fungi. The inflammatory conditions in the mucous membrane are thus often related to the occurrence of fungi in the base of the prosthesis itself, which is extremely difficult to overcome. (Budtz-Jorgensen E., 1974: Scan. J. Dent. Res. 82:151).
Various practical solutions have therefore previously been tried to eliminate the problems discussed above.
In order to improve the retention of the prosthesis it is extremely common to apply a fixing preparation containing adhesive or glue-like material, preferably sodium carboxy methyl cellulose, on the surface of the prosthesis facing the oral mucous membrane, normally termed the mucous membrane surface of the prosthesis. These fixing preparations usually consist of a powder which is applied onto the mucous membrane surface of the prosthesis and which comes into contact with the saliva-coated or saliva-producing mucous membrane, thereby forming a gel with adhesive action. Sometimes the prosthesis is moistened with some water before insertion into the mouth, in order to improve the gel formation. Fixing preparations are also available in the form of a paste which is prepared ready for use when it is manufactured. The gelling or adhesive agent of fixing preparations is generally sodium carboxy methyl cellulose.
The method described enables the wearer to improve the fixing of the prosthesis in a simple manner. For this reason it is often used. However, there are certain drawbacks, particularly if the composition is applied over a long period. The fixing preparation does not inhibit bacteria and fungus flora which normally exist in the oral cavity. Instead, as experience has shown, they may promote the chances of colonization for the micro-organisms. Chemical inhibitors have been added to some types of fixing agents in order to prevent growth, but this has resulted in new problems. The continued use of such chemical inhibitors may easily produce toxic and allergic reactions in the mucous membrane tissues as a result of inhibitor exposure, particularly when the use is extended over a number of years of intermittent application.
Irrespective of whether the denture wearer uses retention composition or not, he must always perform a careful program of oral hygiene comprising daily cleansing of the prosthesis, mouth and any remaining teeth, in order to remove bacteria plaque which is being continuously produced, and the collection of food particles, the occurrence of which is difficult to prevent. (Hedegard E., 1977: Tandlakartidningen Vol. 69, No. 7). The omission of or insufficient prosthesis and oral hygiene may, apart from the more unpleasant feeling of bad odour and taste, give rise to a state of inflammation or even serious alternations in the mucous membrane, known as prosthesis stomatites, and caries attacks on the remaining teeth.
To clean the prosthesis as efficiently and gently as possible dentists recommend brushing with a soft brush and suitable chemical wetting agent, preferably having microbicidal properties. (Andrup B., 1977: Tandlakartidningen, Vol 69, No. 7 and Hesselgren S. G., 1973: Swed. Dent. J., Vol. 66:181).
As to the chemical cleansing there are a number of compositions available which are especially intended for prosthesis. Basically the cleansing composition consists of a combination of two or more chemical substances in powder or tablet form which, when dissolved in usual water, react with each other vigorously producing gas or bubbles (CO.sub.2). It is this effervescing solution which is intended to automatically to remove the coating of bacteria plaque and remnants of fixing agent from the prosthesis when it is immersed in the solution, if successful without further mechanical cleansing.